1. Field of Invention
This invention relates to a semiconductor with a battery unit and, in particular, to the structure of the battery unit. FIG. 1 is an elevational diagrammatic view of a prior art semiconductor device with a battery unit. The battery unit 60 consists of a battery 50 and two battery leads 51 and 52, each of which is jointed or connected at one end to one electrode of battery 50. The battery 50 and the battery leads 51 and 52 are molded in resin, thereby forming the battery unit 60. The battery unit 60 is mounted on the upper surface of the semiconductor device 55 molded in another mass of resin. The battery leads 51 and 52 extend to opposite ends of battery unit 60, and the battery leads 51 and 52 are soldered or welded to connection lead terminals 58 and 59 which are drawn from the semiconductor device within recesses 57 provided at both ends of semiconductor device 55. In addition, the junction within each recess 57 is covered with epoxy resin. This process is called potting and is not shown.
2. Prior Art A battery 50 cannot be replaced in the above prior art assembly because the battery is molded in resin. If the battery fails and must be replaced with a new one, the entire battery unit must be replaced. Thus this prior art system is inefficient. In addition, a power source shuts off when the battery unit is removed, thereby stopping the semiconductor device. Accordingly, a watch having this prior art system does not keep proper time, thereby causing problems, such as the loss of stored data. Further, it is difficult to align the battery unit with the semiconductor device. Therefore, another tool is required in order to correctly position the battery unit and the semiconductor device. Thus this prior art system is inefficient.
Furthermore, in the prior art, in order to protect the two junctions between the battery lead plates and the lead terminals from short-circuiting when the semiconductor device is handled with the bare hands, the junctions are covered with resin in the potting step. However, this step makes battery unit and semiconductor device replacement impossible and increases the number of steps for manufacturing such an assembly device.